A large-area cell of a nuclear facility constitutes a prohibited area when the same is utilized for the storage of containers holding medium-active waste. It is conventional to configure the next adjacent cell as an access or maintenance area wherein bridge cranes from the prohibited area can be serviced. An opening is provided in the partition wall separating the mutually adjacent cells to permit the bridge crane to pass therethrough. The wall opening must be closed during the time that maintenance work is performed on the cell crane in order to shield against radiation present in the prohibited area and to minimize the spread of contamination.
The required shielding against beta, gamma, and neutron rays leads to a situation where the closure body has a high weight dependent upon the size of the opening to be closed and upon the dose rate in the prohibited area. The closure body must be surely placed into its required position.
It has already been suggested to close the wall opening through which the rails of the cell crane pass with aid of bulkheads which are movable in the vertical direction. However, such bulkheads require heavy drives and the transfer of large forces by means of spindles, chains or the like. They are for this reason susceptible to failure and are costly.
It has been further suggested to provide doors that are movable in the transverse direction. These transversely movable doors have the advantage that they require no movement in the vertical direction. However, a significant disadvantage to such doors is that the rails of the cell crane have to be interrupted.